An Integrated Approach to Understanding Noise Stress in Three Species of Freshwater Fish

Date of Award

1-10-2023

Publication Type

Thesis

Degree Name

M.Sc.

Department

Biological Sciences

Keywords

Anthropogenic noise, Behavioural stressors, Cortisol, Freshwater fish, Transcriptional changes

Supervisor

D.Higgs

Supervisor

O.Love

Rights

info:eu-repo/semantics/embargoedAccess

Abstract

Anthropogenic noise has been increasing in aquatic environments over the past decade and has been shown to have negative consequences on a fish’s ability to survive and reproduce. Research has shown that such sound affects fish anatomically, behaviourally, physiologically, and more recently on a molecular level, but more research is needed to understand species-specific responses to noise using an integrated approach. The current study employed behavioural and physiological metrics with novel molecular techniques to determine the effects of anthropogenic noise on three ecologically relevant and auditorily diverse freshwater fish species. Round gobies (Neogobius melanostomus), yellow perch (Perca flavescens), and spottail shiners (Notropis hudsonius) were individually exposed to anthropogenic noise or control sound in an enclosed field setting. Behavioural changes were assessed through video analysis and blood and tissue samples were taken before and after exposure to determine changes in cortisol levels and stress-related gene transcription. The behavioural analysis revealed that only round gobies increased their time spent swimming when exposed to both boat noise and white noise compared to the control. Additionally, all three species displayed more minor startles during boat noise, but only round gobies and spottail shiners exhibited more c-starts as well. Physiologically, there were increases in cortisol levels for all three species, however, there were no differences between treatments likely due to the confounding effects of capture stress. Finally, yellow perch liver samples showed transcriptomic changes with 7 genes upregulated out of a suite of 25. This combined approach addresses the ecological impacts of anthropogenic noise on freshwater fish with various hearing abilities on multiple biological levels. This project better informs conservation-based environmental decisions since it not only considered their behavioural responses, but also their physiological tolerances and allows future studies to identify stress-related genes for minimally invasive health monitoring.

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